Field of the Invention
The present invention relates, in general, to inflatable articles and, more specifically, to inflators for inflatable articles, such as personal flotation devices, life vests, rafts, etc.
Personal flotation devices (PFDs), commonly known as life vests or jackets, and other inflatable articles, such as rafts, etc., have been devised to inflate and serve as a flotation device for a person immersed in water. Such devices typically employ a pressurized gas canister or cylinder, such as a carbon dioxide cylinder, which, when pierced, releases gas to inflate the attached article. A manual operating lever or lanyard is employed to move a spring biased pin into the gas canister to pierce and release the gas therefrom.
While such devices are effective, such manually operated inflators require the use of energy by the wearer to activate the inflator to release the gas to inflate the article. If the wearer is disabled or unconscious, he is unable to actuate the inflator to inflate the article.
To overcome such a problem, automatic inflators have been devised which singly, or in combination with a manual lanyard, automatically inflate a vest or raft when immersed in water. Such automatic inflators typically include a pill or a member formed of a material which is responsive to water and which dissolves or changes in volume or dimension when subject to water. The pill or member, when altered, releases a spring-loaded striker or plunger to pierce the gas canister and release the gas therefrom to inflate the attached article. In other such devices, the disintegration of the pill or member upon exposure to moisture or water causes an explosive charge to detonate to actuate the canister piercing pin.
While such actuators automatically inflate articles without manual intervention, they are not without their deficiencies. Such actuators take a measurable amount of time, i.e., several seconds, for the pill to disintegrate before actuating the device to release the gas and inflate the article. This time delay may be critical in certain uses to prevent injury or drowning of the wearer of the inflatable article. Further, such automatic inflators are relatively unreliable in that they have been proven to operate only two-thirds of the time when exposed to water. Further, such automatic inflators provide little or no ready indication of a fully charged gas canister or any indication of an operative inflator.
Improved automatic inflators have been devised which utilize probes or conductors mounted in the inflator body and which form a part of an electrical circuit used to automatically drive a plunger into the pressurized gas canister. When the housing is fully immersed in water, a circuit is closed between the probes which supplies electric power to an actuating mechanism, i.e., such as an explosive charge which detonates to drive the plunger into the canister. While such inflators are an improvement over previously devised automatic inflators, care must be taken to prevent premature actuation due to a splash of water when the housing is not fully immersed in water. Further, such improved automatic inflators still provide no indication of a spent or empty gas canister nor the operative state of the inflator actuating mechanism.
Further, such previously devised inflators require the replacement of certain parts, such as the water soluble member or the detonator, before they can be used again. This adds to the cost of the inflator and minimizes its efficient usage over a long period of time.
Certain automatic inflators have been devised which address most of these deficiencies, such as those noted in the above "Cross Reference to Related Applications." In one of these devices, a control unit, in response to a signal from water sensor probes, activates a motor-gear means to rotate a cam which engages a plunger mounted in a sealed housing and urges the plunger and a piercing pin attached to the end of the plunger forcibly into a sealed gas canister. In the other device, the control means, in response to an output from a water sensor, activates a motor-gear means which retracts a slider allowing a spring biased ram to move under spring force and drive a plunger and piercing pin into the sealed gas canister. In this device, the force of the ram acting on the slider is at a 90.degree. angle with respect to the slider which results in high frictional forces and motor loads. This leads to the need for larger motors which increases the overall size of the automatic inflator. However, while these automatic inflators overcome many of the deficiencies found with previously devised automatic inflators for inflatable articles, it has been found that further improvements could be made to these automatic inflators to improve their reliability, reduce their size and the number of individual components, as well as to simplify their construction.
Thus, it would be desirable to provide an automatic inflator for inflatable articles which automatically inflates an inflatable device without user intervention. It would also be desirable to provide an automatic inflator which quickly inflates an inflatable article when immersed in water. It would also be desirable to provide an automatic inflator which can be internally reset for successive operations without the need for replacing spent parts. Finally, it would be desirable to provide an automatic inflator for inflatable articles which provides an easily visible indication of the condition of the gas canister, i.e., whether charged or pierced, as well as the operative state of the inflator actuating mechanism.